Method for preparing concrete water-reducing agent by grafting compound side chain of polycarboxylic acid modified acid halide

Abstract

The invention discloses a method for preparing concrete water reducing agents from polycarboxylic acid modified acyl halide grafted composite side chains, and belongs to the field of water reducing agents. By the aid of the method for polymerizing main chains, modifying acyl halide, polymerizing cationic side chains and then carrying out grafting reaction, polycarboxylic acid modified acyl halide grafted composite side chain type concrete reducing agent materials which are excellent in performance can be prepared. The method includes carrying out free radical polymerization on unsaturated carboxylic acid monomers to obtain the polycarboxylic acid main chains; modifying carboxylic acid groups on the main chains to obtain acyl halide groups; forming oxidation-reduction initiation systems from high-valence ceric salt and alcohol, initiating polymerization of unsaturated cationic quaternary ammonium salt monomers by the aid of the oxidation-reduction initiation systems to obtain the hydroxyl-terminated cationic side chains; carrying out the grafting reaction on the polycarboxylic acid main chains with the acyl halide groups, the hydroxyl-terminated cationic side chains and polyethylene glycol compounds to obtain the concrete water reducing agents. The method has the advantages that owing to modes for modifying the acyl halide by polycarboxylic acid and grafting the cationic side chains and polyethylene glycol side chains, composite side chain structures can be synthesized, reaction procedures are simple and are easy to control, energy can be saved, the method is high in efficiency, and excellent water reduction slump retaining and high-resistant clay composite effects can be realized.

Description

technical field

[0001] The present invention relates to the technical field of a composite side chain type concrete water reducer, in particular to a method that adopts an unsaturated carboxylic acid monomer to first polymerize the main chain, then modify the acyl halide group, then polymerize the cationic side chain, and then graft the main side chain. The specific preparation method of reaction synthesis composite side chain type concrete water reducer. Background technique

[0002] As the third generation of water reducer, polycarboxylate water reducer with polycarboxylic acid as the main molecular structure has become an indispensable and important component in concrete. It makes an important contribution to the preparation and realization of the excellent characteristics of high-performance concrete. With the widening of various auxiliary materials in concrete, the adaptability of concrete superplasticizers to various raw materials has become the focus of researchers. ...

Examples

Embodiment 1

[0029] First, add 7.21g of acrylic acid, 10.81g of water, 0.96g of mercaptopropionic acid, and 7.94g of a 12% sodium persulfate aqueous solution to the reactor in sequence, and the stirring time between each addition is 11 minutes, and the temperature is raised to 68°C. Polymerization reaction, reacted for 6 hours, and obtained the aqueous solution of the polycarboxylic acid main chain; vacuumized the obtained aqueous solution of the polycarboxylic acid main chain to remove the moisture in the system, added 45.45g of 1,4-dioxane, stirred for 11 minutes, and cooled in an ice-water bath. Add 4.16g of thionyl bromide dropwise to the reactor within 0.9 hours, continue to heat up to 50°C and react at a constant temperature for 4 hours, and simultaneously use 20.2g of potassium hydroxide solution with a mass fraction of 25% to absorb the gas produced by the reaction, to obtain Polycarboxylic acid-acyl bromide solution; 29.91g methacryloyloxyethyltrimethylammonium chloride and 0.48g i...

Embodiment 2

[0031] After storing the 30% concrete water reducer solution obtained in Example 1 at 6° C. for 30 days, its implementation effect was measured.

Embodiment 3

[0033] First add 4.8g acrylic acid, 3.87g fumaric acid, 8.67g water, 2.16g sodium allyl sulfonate, 8.56g mass fraction in the reactor successively and be the ammonium persulfate aqueous solution of 8%, and every feeding interval stirring time After 8 minutes, the temperature was raised to 55°C for polymerization reaction, and the reaction was carried out for 7 hours to obtain an aqueous solution of polycarboxylic acid main chain; the obtained aqueous solution of polycarboxylic acid main chain was evacuated to remove moisture in the system, and 16.99 g of dimethylformamide was added, and stirred In 18 minutes, add 8.31g of thionyl bromide dropwise to the reactor within 0.5 hours under ice-water bath conditions, continue to heat up to 40°C and react at a constant temperature for 4.5 hours. The gas generated by the reaction is the polycarboxylic acid-acyl bromide solution; 48.8g of acryloyloxyethyltrimethylammonium chloride and 0.84g of cyclohexanol are added to another reactor, a...

technical field

[0001] The present invention relates to the technical field of a composite side chain type concrete water reducer, in particular to a method that adopts an unsaturated carboxylic acid monomer to first polymerize the main chain, then modify the acyl halide group, then polymerize the cationic side chain, and then graft the main side chain. The specific preparation method of reaction synthesis composite side chain type concrete water reducer. Background technique

[0002] As the third generation of water reducer, polycarboxylate water reducer with polycarboxylic acid as the main molecular structure has become an indispensable and important component in concrete. It makes an important contribution to the preparation and realization of the excellent characteristics of high-performance concrete. With the widening of various auxiliary materials in concrete, the adaptability of concrete superplasticizers to various raw materials has become the focus of researchers. ...

Examples

Embodiment 1

[0029] First, add 7.21g of acrylic acid, 10.81g of water, 0.96g of mercaptopropionic acid, and 7.94g of a 12% sodium persulfate aqueous solution to the reactor in sequence, and the stirring time between each addition is 11 minutes, and the temperature is raised to 68°C. Polymerization reaction, reacted for 6 hours, and obtained the aqueous solution of the polycarboxylic acid main chain; vacuumized the obtained aqueous solution of the polycarboxylic acid main chain to remove the moisture in the system, added 45.45g of 1,4-dioxane, stirred for 11 minutes, and cooled in an ice-water bath. Add 4.16g of thionyl bromide dropwise to the reactor within 0.9 hours, continue to heat up to 50°C and react at a constant temperature for 4 hours, and simultaneously use 20.2g of potassium hydroxide solution with a mass fraction of 25% to absorb the gas produced by the reaction, to obtain Polycarboxylic acid-acyl bromide solution; 29.91g methacryloyloxyethyltrimethylammonium chloride and 0.48g i...

Embodiment 2

[0031] After storing the 30% concrete water reducer solution obtained in Example 1 at 6° C. for 30 days, its implementation effect was measured.

Embodiment 3

[0033] First add 4.8g acrylic acid, 3.87g fumaric acid, 8.67g water, 2.16g sodium allyl sulfonate, 8.56g mass fraction in the reactor successively and be the ammonium persulfate aqueous solution of 8%, and every feeding interval stirring time After 8 minutes, the temperature was raised to 55°C for polymerization reaction, and the reaction was carried out for 7 hours to obtain an aqueous solution of polycarboxylic acid main chain; the obtained aqueous solution of polycarboxylic acid main chain was evacuated to remove moisture in the system, and 16.99 g of dimethylformamide was added, and stirred In 18 minutes, add 8.31g of thionyl bromide dropwise to the reactor within 0.5 hours under ice-water bath conditions, continue to heat up to 40°C and react at a constant temperature for 4.5 hours. The gas generated by the reaction is the polycarboxylic acid-acyl bromide solution; 48.8g of acryloyloxyethyltrimethylammonium chloride and 0.84g of cyclohexanol are added to another reactor, a...

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